When to Shift

The magazine Chevy High Performance in the July 2004 issue tackles the ever questioned issue of shifting to maximize torque or horsepower. Of four theories put forth, the looser is shifting to maximize average torque. Maximizing average horsepower looses out slightly to shifting out of the current gear at the same horsepower level that you enter into the next gear. To determines the optimum shift points you have a chassis dyno operator plot rear wheel torque versus speed or rear wheel HP versus speed (since they are related). The dyno operator can provide the rpm where the curves intersect. One really needs to read the article, then too, while this should lay to rest the arguements it probably will be forgotten only to let the arguments start again.

|UPDATED|5/27/2004 9:44:12 PM (AZT)|/UPDATED|

I should add that back in the 60's when I was active on drag strips the Isky cam manufacturer claimed the best shifting done was to maximize the area under the HP versus rpm curve. That was another way of saying what the magazine article claims.
Today's cars (C5 346 LS1) beat yesterday's cars ( My C3 427 L71) essentially because manufacturers realize that mid range torque adds so much to the equation that they no longer use the large valve overlap to maximize and therefore make HP peaky. Roller cams providing higher lifts with less overlap still fill those cylinders!